scholarly journals Nutrient removal by Rotala rotundifolia: a superior candidate for ecosystem remediation at low temperatures

RSC Advances ◽  
2020 ◽  
Vol 10 (49) ◽  
pp. 29139-29146
Author(s):  
Yunlong Yang ◽  
Xiaying Zhang ◽  
Jibo Xiao ◽  
Shuyi Chu ◽  
Zhida Huang

Temperature is an extremely important factor affecting the nutrient (mainly nitrogen and phosphorus) removal of aquatic macrophytes.

2012 ◽  
Vol 518-523 ◽  
pp. 2597-2603
Author(s):  
Na He ◽  
Zhan Xiang Sun ◽  
Yu Long Zhang ◽  
Ming Da Liu

This study focused on the comparisons between nitrogen and phosphorus removal rates from the simulated wastewater using various kinds of aquatic plants (4 emergent and 3 floating plants). Results showed that aquatic plants has a significant effect on the removal of NO3--N and TP, but has a less effect on NH4+-N. Among the four emergent plants, the order of NO3--N removal capacities was: S. sagittifolia > S. tabernaemontani > T. latifolia > A. calamus. But for TP, the order was: T. latifolia > A. calamus > S. tabernaemontani > S. sagittifolia. To the floating plants, the order of NO3--N and TP removal capacities were: E. crassipes > P. stratiotes. The ANOVA analyses showed that there was a significant difference between planted treatments and unplanted treatment for the removal of NO3--N and TP. The study suggests that the treatment of simulated wastewater using the aquatic macrophytes was effective in the removal of nutrients.


2014 ◽  
Vol 69 (9) ◽  
pp. 1961-1969 ◽  
Author(s):  
Bonnie J. Glaister ◽  
Tim D. Fletcher ◽  
Perran L. M. Cook ◽  
Belinda E. Hatt

Biofilters have been shown to effectively treat stormwater and achieve nutrient load reduction targets. However, effluent concentrations of nitrogen and phosphorus typically exceed environmental targets for receiving water protection. This study investigates the role of filter media, vegetation and a saturated zone (SZ) in achieving co-optimised nitrogen and phosphorus removal in biofilters. Twenty biofilter columns were monitored over a 12-month period of dosing with semi-synthetic stormwater. The frequency of dosing was altered seasonally to examine the impact of hydrologic variability. Very good nutrient removal (90% total phosphorus, 89% total nitrogen) could be achieved by incorporating vegetation, an SZ and Skye sand, a naturally occurring iron-rich filter medium. This design maintained nutrient removal at or below water quality guideline concentrations throughout the experiment, demonstrating resilience to wetting–drying fluctuations. The results also highlighted the benefit of including an SZ to maintain treatment performance over extended dry periods. These findings represent progress towards designing biofilters which co-optimise nitrogen and phosphorus removal and comply with water quality guidelines.


2006 ◽  
Vol 53 (9) ◽  
pp. 169-175 ◽  
Author(s):  
K. Hamada ◽  
T. Kuba ◽  
V. Torrico ◽  
M. Okazaki ◽  
T. Kusuda

A shortage of organic substances (COD) may cause problems for biological nutrient removal, that is, lower influent COD concentration leads to lower nutrient removal rates. Biological phosphorus removal and denitrification are reactions in which COD is indispensable. As for biological simultaneous nitrogen and phosphorus removal systems, a competition problem of COD utilisation between polyphosphate accumulating organisms (PAOs) and non-polyphosphate-accumulating denitrifiers is not avoided. From the viewpoint of effective utilisation of limited influent COD, denitrifying phosphorus-removing organisms (DN-PAOs) can be effective. In this study, DN-PAOs activities in modified UCT (pre-denitrification process) and DEPHANOX (post-denitrification ptocess) wastewater treatments were compared. In conclusion, the post-denitrification systems can use influent COD more effectively and have higher nutrient removal efficiencies than the conventional pre-denitrification systems.


2019 ◽  
Vol 118 ◽  
pp. 01023 ◽  
Author(s):  
Liwei Xiao ◽  
Hong Jiang ◽  
Chao Shen ◽  
Ke Li ◽  
Lei Hu

In this study, plant growth and nitrogen and phosphorus removal efficiency in lab-scale CWs by five plants (H. vulgaris, N. peltatum, N. tetragona, N. pumilum, S. trifolia) in winter in Sichuan basin was evaluated. H. vulgaris and N. tetragona would well adapt to the winter wetland environment, and the relative growth at the end of the experiment was 89.83% and 66.85%, respectively. In winter, H. vulgaris kept growing with accumulated stems and leaves, while growth of N. tetragona was mainly caused by the growth of roots and stems underwater. In addition, during the winter, removal efficiencies were 66.29%, 57.47%, 54.78%, 55.47%, 41.66% of TN and 62.40%, 69.75%, 69.97%, 65.65%, 76.55% of TP for each planted CWs respectively. The results indicated that the removal of nitrogen and phosphorus from CWs was mainly achieved by substrate, while a small portion was attributed by plant. However, plants like H. vulgaris and N. tetragona, in the CWs in winter can play the role of landscaping. Thus, H. vulgaris could be considered as a suitable and effective nutrient removal plant for treatment of nitrogen and phosphorus water in winter wetlands in Sichuan basin.


2015 ◽  
Vol 73 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Monireh Lashkarizadeh ◽  
Giulio Munz ◽  
Jan A. Oleszkiewicz

The impact of pH variation on aerobic granular sludge stability and performance was investigated. A 9-day alkaline (pH = 9) and acidic (pH = 6) pH shocks were imposed on mature granules with simultaneous chemical oxygen demand (COD), nitrogen and phosphorus removal. The imposed alkaline pH shock (pH 9) reduced nitrogen and phosphorus removal efficiency from 88% and 98% to 66% and 50%, respectively, with no further recovery. However, acidic pH shock (pH 6) did not have a major impact on nutrient removal and the removal efficiencies recovered to their initial values after 3 days of operation under the new pH condition. Operating the reactors under alkaline pH induced granules breakage and resulted in an increased solids concentration in the effluent and a significant decrease in the size of the bio-particles, while acidic pH did not have significant impacts on granules stability. Changes in chemical structure and composition of extracellular polymeric substances (EPS) matrix were suggested as the main factors inducing granules instability under high pH.


2001 ◽  
Vol 43 (6) ◽  
pp. 185-192 ◽  
Author(s):  
E. Choi ◽  
Z. Yun ◽  
Y. Park ◽  
H. Lee ◽  
H. Jeong ◽  
...  

Experimental investigations were performed to determine the possibility of simultaneous biological nitrogen and phosphorus removal during various biofilm processes in conjunction with biofilm characterisation, especially extracellular polymeric substance (EPS). Since biological nitrogen removal requires an alternating exposure of anaerobic-anoxic-oxic conditions in the bulk liquid that surrounds the biofilm growth media, a sequencing batch reactor (SBR)-type operation was used. Various materials including expanded clay, polystyrene, polyurethane, and acrylic materials were used as the biofilm growth support medium. Simultaneous nitrogen and phosphorus removal was possible with SBR, but it was postulated that nutrient removal efficiencies varied with film thickness. Thinner biofilm promoted nitrification and phosphorus removal, but thicker biofilm enhanced denitrification and reduced phosphorus removal. EPS contents were similar regardless of support media types or biofilm configuration, but EPS contents gradually increased as the film growth continued after backwashing. EPS contents were increased with increased nitrogen removal, but it was difficult to define its relation with phosphorus removal. In addition, suspended solids removal was correlated well with the EPS content in the biofilms.


1997 ◽  
Vol 36 (12) ◽  
pp. 19-27 ◽  
Author(s):  
S. H. Chuang ◽  
C. F. Ouyang ◽  
H. C. Yuang ◽  
S. J. You

This study examines the effects of sludge retention time (SRT) and dissolved oxygen (DO) on COD, nitrogen and phosphorus removal in a combined activated sludge - biofilm process. Various SRT (5, 10, 12 and 15 days) and dissolved oxygen (0.1, 0.5, 1.0 and 2.0 mg/l in aerobic stage) conditions are performed during the hybrid process. Experimental results indicate that SRT significantly affects the behavior of nitrogen and phosphorus removal, although the variation of COD removal is only slight in different SRT experiments. The SRT should be controlled for longer than 10 days to achieve efficient nitrogen removal. However, a SRT less than 12 days is deemed necessary to complete the phosphorus removal. The process displays similar characteristics when dissolved oxygen is operated between 1.0 to 2.0 mg/l in the aerobic stage. Moreover, analyzing polyhydroxyalkanoates (PHAs) reveals that phosphorus release and uptake are closely related to PHAs accumulation and utilization, respectively, during anaerobic, anoxic and aerobic stages of the process. The ratio of phosphorus uptake and PHAs utilized, rP/PHAs, denotes a dissimilar trend during anoxic and aerobic stages. The sludge has a high efficiency in utilizing PHAs for phosphorus uptake in anoxic stage when it is under lower COD-SS loading conditions. The value of rP/PHAs ranges from approximately 0.1 to 1.0 mg P/mg PHAs. In addition, experimental results also demonstrate that anoxic phosphorus uptake can improve phosphorus removal in biological nutrient removal processes.


2001 ◽  
Vol 44 (1) ◽  
pp. 181-186 ◽  
Author(s):  
U. Altinbas

Nutrient removal was investigated in a packed bed column, which was operated by changing of aerated and non-aerated periods. Good removal efficiencies for nitrogen and phosphorus were obtained at long aeration period. Highest nitrification efficiency was observed in run3 because the aeration period was enough to allow nitrification. NO3 concentration was not significantly changed during the cycle, because of simultaneous denitrification during aerobic stage. Nitrogen and phosphorus removal efficiencies reached to 71 and 74% in run3 respectively. Effluent concentrations of TKN, Tot.P, NH4 and NO3 were found as 3.8, 3, 1 and 2.5 mg/l respectively.


1993 ◽  
Vol 28 (10) ◽  
pp. 317-324
Author(s):  
Bjarne Hjorth

The general Danish standards for discharge from municipal waste water treatment plants larger than 5000 PE require extended nitrogen and phosphorus removal to 8 mg/l total-nitrogen and to 1.5 mg/l phosphorus. In many cases the local authorities require that the same standards have to be met by smaller plants down to 500 PE. In some cases even tighter standards are set. As plants for extended nitrogen and phosphorus removal for smaller communities should not necessarily look like the large plants, new concepts have been developed. Combined nitrogen and phosphorus removal based on one activated sludge tank and one clarifier has proved to be advantageous both technically and economically in order to meet the above mentioned standards given under the Danish climate conditions with water temperatures of 38°C during winter. Six plants ranging from 600-2,500 PE and further three plants from 4,000-7,300 PE are now in operation. This paper gives a general description of the design and the operation of these plants. The plants operate by means of simultaneous precipitation and a special intermittent operational strategy or nitrification/denitrification. Operational results from the five plants with up to 4 years of operation show average concentrations of nitrogen and phosphorus of 5-6 mg/l and 0.4-0.8 mg/l, thereby leaving a rather large margin to the general Danish standards. As regards competition, the concept has proven to be very competitive in the range of 1,000-10,000 PE.


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